Sunscreen: the truth behind SPF

Posted:
Friday, June 4, 2010 5:43 PM EDT

WATERLOO (KWWL) -- With summer upon us, now is the time to start thinking of protecting your skin when outdoors. Sunscreen is important to use, no matter what SPF you choose, but there are misconceptions about what the numbers really mean.

SPF 15 blocks 93% of UVB rays.

SPF 30 blocks 97% of UVB rays.

SPF 50 blocks 98% of UVB rays.

Those numbers are according to the Skin Cancer Foundation. The reality behind the numbers is something to take into consideration when making a purchase.

Another tip: if you're applying a spray-on sunscreen on a windy day, spray it in your hand and rub it in.